1. Field of the Invention
The invention is directed to a disengageable universal shaft for rolling mill. The shaft having a flange on the roll side that can be coupled centrally with the coupling sleeve attached to the roll shaft, and a flange at the gear unit side that is connected with the roll drive via a spline shaft that enables the disengaging movement. The spline shaft being penetrated centrally by the extensible part of a piston-cylinder unit. The relative longitudinal movement between the spline shaft and the flange which brings about the disengagement of the supportable universal shaft being introduced by way of the pressure-medium actuation of the piston-cylinder unit.
2. Description of the Related Art
A generic device for engaging and disengaging universal shafts for rolling mill drives is known from German Patent 19 02 665. The universal shaft described therein has a telescoping length compensation in that the shaft is divided into two parts which are interconnected via a spline shaft so as to be capable of transmitting torque. In order to disengage the universal shaft when changing rolls, the two parts of the universal shaft are moved relative to one another by hydraulic cylinders provided in the interior of these parts or at their surface. The disengaged universal shaft is supported in the region of the flange connections between the drive and output.
Universal shafts of this type or of a similar type have been known for many years and are used in a multitude of rolling mill drives. The cost of devices for support and longitudinal displacement is very high, particularly for large-weight universal shafts used in heavy rolling mills. Manipulation of these universal shafts involves not only manual labor but a considerable expenditure of time. For this reason, continual efforts are made to simplify the disengagement of universal shafts in order to economize on labor and time when changing rolls.
A further disadvantage of the known universal shaft is that costly mechanisms are required for telescoping length compensation. The piston-cylinder unit provided in the interior of the universal shaft in the known solution is costly and difficult to maintain owing to poor accessibility. When the piston-cylinder unit is arranged externally, as is also suggested in the prior art, additional manual labor and time-consuming manipulation using crane installations are required for coupling, which is likewise a negative factor in the time required for changing the rolls The two-part construction of the universal shaft leads to wear in the displacing parts as a result of the high driving torques to be transmitted, even when these displacing parts are produced and maintained at great cost.